This invention generally relates to the art of electrical connectors and, particularly, to an electrical connector assembly for effecting a connection between two circuit boards.
A variety of electrical connectors have been used to make electrical connections between the circuits on different printed circuit boards. These printed circuit boards must be joined together with connectors in a manner to effectively and reliable interconnect the circuits on one circuit board to the circuits on another circuit board. This is done by a pair of mating connectors which are surface mount connectors and may include a male or plug connector mateable with a female or receptacle connector to form a board-to-board electrical connector assembly.
As stated above, both connectors of the electrical connector assembly are surface mount connectors. Both connectors typically have a low profile and have some form of mechanism to lock the connectors together. Locking mechanisms which have been used heretofore range from simple frictional forces between the terminals of the mating connectors to positive latching detents or recesses on the dielectric housings of the connectors. Frictional forces between the terminals have not been consistently adequate to hold the connectors together and, in some instances, the frictional forces have been so great that mating the connectors have required very high forces. Latching detents between the terminals can work well, but the latching devices must be located very accurately at preselected distances which requires manufacturing tolerances which are not practical to maintain with such connectors. If these tolerances are not maintained, too much xe2x80x9cplayxe2x80x9d or movement exists between the boards. Latching detents between the connector housings have not worked well because movement of the plastic surfaces over one another creates abrasion which increases the insertion and withdrawal forces and which permanently wears the parts. The present invention is directed to solving these problems by providing a system which holds the connectors together and, in fact, does so with minimal mating forces.
An object, therefore, of the invention is to provide a new and improved board-to-board electrical connector assembly for effecting a connection between two circuit boards.
In the exemplary embodiment of the invention, the connector assembly includes a first connector having a dielectric housing for mounting on a first circuit board. A plurality of first terminals are mounted on the dielectric housing. Each terminal includes a tail portion for connection to an appropriate circuit trace on the first circuit board, and a convex contact portion defining a continuous arcuate contact surface. A second connector has a dielectric housing for mounting on a second circuit board. A plurality of second terminals are mounted on the dielectric housing of the second connector and each second terminal includes a tail portion for connection to an appropriate circuit trace on the second circuit board. Each second terminal includes a contact projection for sliding over the continuous arcuate contact surface of a first terminal upon mating of the connectors.
With the above construction and interengagement of the terminals of the connector assembly, initial engagement of the contact projection of each second terminal with the convex contact portion of a first terminal is at minimal engaging forces which increase as the contact projection slides over the convex contact portion and then decreases to allow the connectors to mate and the circuit boards to come together with minimal mating forces at a mated condition of the connectors.
According to one aspect of the invention, the contact projection of each second terminal is at the distal end of a flexible contact arm which comprises one leg of a U-shaped contact section of the second terminal. The dielectric housing of the first connector includes a plug portion mateable in the U-shaped contact section of the second terminals. The convex contact portions of the first terminals are at one side of the plug portion for engagement with the contact projections of the second terminals of the second connector.
As disclosed herein, the U-shaped contact section of each second terminal is connected to a mounting section for mounting the second terminal in the dielectric housing of the second connector. The tail portion of each second terminal projects from the mounting section thereof. According to another aspect of the invention, the first terminals are generally U-shaped, with each first terminal having one leg of the U-shape defining the convex contact portion and the other leg of the U-shape defining a mounting portion for mounting the first terminal in the dielectric housing of the first connector. The tail portion of the first terminal is at a distal end of the mounting portion thereof. The housing of the first connector has an open space between the convex contact portion and the mounting portion of each first terminal so that the convex contact portion is free to flex upon engagement with the second terminal of the second connector.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.